FBN1 and Marfan syndrome: Despite the additional deletion of five contiguous genes (SLC24A5, MYEF2, CTXN2, SLC12A1, DUT), our patients: 2, 3 and 4 had no other features than those that can be attributed to the deletion of FBN1. The same was observed in two patients from Hilhorst-Hofstee et al. [18] found to have deletion of 9 genes including FBN1. These findings not only support the role of haploinsufficiency of FBN1 in the pathogenesis of MFS, but also suggest that the function of SLC24A5, MYEF2, CTXN2, SLC12A1, DUT may not be impaired by complete loss of an entire allele.